Noun

(en-noun)

A state of great disorder or uncertainty.

*{{quote-news, year=2012, date=June 19, author=Phil McNulty, work=BBC Sport

, title=]http://www.bbc.co.uk/sport/0/football/18181971 England 1-0 Ukraine] , passage=Oleg Blokhin's side lost the talismanic Andriy Shevchenko to the substitutes' bench because of a knee injury but still showed enough to put England through real turmoil in spells.}}

Harassing labour; trouble; disturbance.

* Shakespeare

And there I'll rest, as after much turmoil , / A blessed soul doth in Elysium.

*, chapter=7

, title= The Mirror and the Lamp , passage=The turmoil went on—no rest, no peace. […] It was nearly eleven o'clock now, and he strolled out again. In the little fair created by the costers' barrows the evening only seemed beginning; and the naphtha flares made one's eyes ache, the men's voices grated harshly, and the girls' faces saddened one.}}

Noun

(wikipedia entropy)

(thermodynamics, countable)

# strictly thermodynamic entropy . A measure of the amount of energy in a physical system that cannot be used to do work.

The thermodynamic free energy is the amount of work that a thermodynamic system can perform; it is the internal energy of a system minus the amount of energy that cannot be used to perform work. That unusable energy is given by the entropy''' of a system multiplied by the temperature of the system.''^{[http://en.wikipedia.org/wiki/Thermodynamic_free_energy]} ''(Note that, for both Gibbs and Helmholtz free energies, temperature is assumed to be fixed, so '''entropy is effectively directly proportional to useless energy.)

# A measure of the disorder present in a system.

Ludwig Boltzmann defined entropy''' as being directly proportional to the natural logarithm of the number of microstates yielding an equivalent thermodynamic macrostate (with the eponymous constant of proportionality). Assuming (by the fundamental postulate of statistical mechanics), that all microstates are equally probable, this means, on the one hand, that macrostates with higher '''entropy''' are more probable, and on the other hand, that for such macrostates, the quantity of information required to describe a particular one of its microstates will be higher. That is, the Shannon '''entropy''' of a macrostate would be directly proportional to the logarithm of the number of equivalent microstates (making it up). In other words, thermodynamic and informational entropies are rather compatible, which shouldn't be surprising since Claude Shannon derived the notation 'H' for information '''entropy from Boltzmann's H-theorem.

# The capacity factor for thermal energy that is hidden with respect to temperature [http://arxiv.org/pdf/physics/0004055].

# The dispersal of energy; how much energy is spread out in a process, or how widely spread out it becomes, at a specific temperature. [http://www.entropysite.com/students_approach.html]

(statistics, information theory, countable) A measure of the amount of information and noise present in a signal. Originally a tongue-in-cheek coinage, has fallen into disuse to avoid confusion with thermodynamic entropy.

(uncountable) The tendency of a system that is left to itself to descend into chaos.